Heald B, Mester J, Rybicki L et al.
Cleveland Clinic, Cleveland, OH, USA.
Editor’s note: Cowden syndrome (CS) is a multisystemic hamartomatous polyposis syndrome that confers an increased risk of thyroid, breast, and endometrial cancers. Up to 80% of patients with CS have a germline mutation in the phosphatase and tensin homologue (PTEN) tumor suppressor gene on chromosome 10 (J Genet Counsel 2009;18:13–27). PTEN plays a role in the phosphoinositide-3-kinase/protein kinase B and mitogen-activated kinase cell signaling pathways, which are involved in the regulation of cellular growth and cancer.